Television antenna



J 20, 17959 L. J. LYNCH ET AL 2,870,443

TELEVISION ANTENNA I Filegi April 15, 1953 Leonard J Lynch E Harozcz H zz'shrock,

United States Patent TELEVISION ANTENNA Leonard J. Lynch, De Kalb, andHarold H. Tishrock,

Evanston, Ill.

Application April 15, 1953, Serial No. 349,012

6 Claims. (Cl. 343-812) This invention relates to television antennas,and has for its principal object the provision of improvements in theantenna disclosed in the copending application of Leonard J. Lynch,Serial No. 215,332, filed March 13, 1951, now Patent No. 2,776,430issued Jan. 1, 1957.

In the copending application mentioned, the antenna disclosed consistsof two groups of three horizontally disposed, vertically spaced,parallel, metal rods mounted in coplanar relationship on opposite sidesof a vertical supporting-mast by means of suitable insulators, with avertical metal rod on each side of the mast electrically connecting themid-points of the horizontal rods of each group. The inner end of themiddle rod of each group is cross-connected electrically with the innerends of the upper and lower rods of the other group and a lead-in wireto the receiving set is' electrically connected to the inner ends ofthese middle rods to connect the antenna with the set. The antenna hascooperating with it a reflector disposed in spaced parallel relationshipbehind the antenna and arranged to be turned with it so that the antennafaces the selected station and the reflector shields the antenna againstinterference from another station on the same channel. The reflectorconsists of two sets of five horizontal parallel metal rods disposed inequally vertically spaced coplanar relationship on opposite sides of asupporting mast, the rods of each set rigidly electrically connected atopposite ends by vertical rods and supported on the mast in insulatedrelationship to one another and to the mast. The five rods in each setconnected as described form four loops on each side of the mast, and anycombination of loops can be used in the tuning of the reflector toprovide good reception in the various channels. The reflector is placedas close as possible to the antenna to prevent as much interference aspossible from the side and yet allow maximum gain on the high band.

The reflector, in other words, may be considered as an element placed ina horizontal plane behind a dipole of the proper length and at theproper spacing to permit forward gain. This gain results from wavesinducing a current in the reflector element and radiating back to thedipole in phase with the incoming signal. This is commonly referred toas a regenerative eflect and is utilized in a novel manner by virtue ofa change in the construction of the antenna proper, in accordance withour invention, whereby the antenna-reflector combination is designed tofit the needs of any area whether it be a gain on all channelsconcerned, or be a need for elimination or reduction of co-channel orinterchannel interference.

The invention is illustrated in the accompanying drawing, in which- Fig.1 is a perspective view of our improved antenna, the same being shownwithout the reflector;

Fig. 2 is a face view of the reflector, which is the same as thatdisclosed in the copending application;

Fig. 3 is a perspective view of the antenna-reflector Patented Jan. 20,1959 assembly, the reflector being a unit purchasable separately andcombinable with existing antennas, and

Figs. 4 to 6 are diagrams used in describing the operation.

The same reference numerals are applied to corresponding parts in theseviews.

Referring first to Fig. l, the antenna comprises a vertical supportingmast 11, having two sets of horizontally disposed, vertically spaced,parallel, metal rods 12, 13, and 14, and 12', 13 and 14 mounted incoplanar relationship but on opposite sides of the mast 11, as by meansof insulators 15 to which the rods or elements are suitably secured ininsulated relation to one another and to the mast. A verticalmetal rod16 connects the midpoints of only rods 12 and 14 in rigid relationship,and another vertical metal rod 17 connects the midpoints of only rods 12and 14' in rigid relationship, rods 13 and 13' being insulated from rods16 and 17, as indicated at 18 and 18. The inner ends of the middle rods13 and 13' are cross-connected with the upper and lower rods 12 and 14and 12' and 14' by conductors 19 to complete the antenna, and there is aconducting line 20 connected therewith and extending to the set. Theantenna as thus far described has the general appearance of a flyswatter and is often so named.

Referring next to Fig. 2, the reflector consists of two sets ofhorizontal, parallel, metal rods 2125 and 2125 disposed in verticallyspaced coplanar relationship on opposite sides of a supporting mast 26,the rods of each set being rigidly electrically connected by verticalrods 27 and 28 at their inner and outer ends, respec tively, andsupported on the mast 26 by insulators 29 in insulated relation to oneanother and to the mast. The vertical array of rods 21, 23, and 25 and21', 23, and 25 in the reflector is similar to the vertical array ofrods 12-14 and 1214 on the antenna, the rods 22 and 24 and 22' and 24 inthe reflector being midway between rods 21, 23, and 25, and 21, 23, and25', respectively. The reflector is mounted behind the antenna, as shownin Fig. 3, in a fixed, spaced, parallel, relationship, the masts 11 and26 being cut off just below the antenna and reflector and clampedtogether, as shown at 30, and to a main mast 31, which is, of course,arranged to be turned in the usual way, so that the antenna portionfaces the selected station and the reflector portion shields the antennaportion against interference from another station on the same channel.Four loops are formed on each side of the mast 26 by the interconnectedrods, and shorting bars 32, which are disposed between the ends of therods 21-25 and 2125, are adapted to connect any combination of loopspermanently, or, as disclosed in the copending application, these bars32 may be normally in spaced disconnected relation to the rods and formthe armature parts of relays arranged to be selectively energized bymanual operation of selector switches to use any combination of loops inthe tuning of the reflector for good reception of programs in anychannel. Thus, some of the channels require actuation of as many as fourbars 32 at a time, while others require the operation of only two bars.in many installations, however, and this is true especially in fringeareas where the only available good reception is from one direction, thebars 32 may be fixed permanently to provide a given combination of loopsfound to give the best results, and'in some of these installations oneor more of the rods 2125 and 2125' may be omitted if not needed for theloop combination selected.

In order to understand the operation, the diagrams Figs. 4-6 will bereferred to. Consider first two dipoles like rods 13-14 and 13'14, asillustrated in Fig-5, placed one above the other, one-half wave, lengthapart.

3 These dipoles are cut for full wave length on the high band andcross-connected by wires 19, and the incoming signal indicated by thevoltage curves X strike the dipoles at the same instant so that theelectrical charge on each element will be in the same phase, voltage andcurrent. If the energy radiated from one dipole travelled through theair to the other dipole, it would arrive out of phase and the chargewould be zero, but that is not true here, because the wires 19crossconnecting the dipoles carry the R. F. voltage and current and addthe charges in phase. Carrying this a step further, consider next thatanother dipole 1212' is added, and it is evident that it, being also ahalf-wave length away from the middle dipole 13-13, adds its signalcharge. The gain of this antenna has been measured and amounts to 12 db.The operation thus far has dealt only with the high band, namely,channels 7-13, with each of these channels at a particular wave length.The low band, channels 26, are received without interfering with thegain of the high band. It will be noticed in Fig. 5 that the voltagecurves X are alike and that they cross each dipole one-half way from themiddle of each dipole. This point has substantially zero voltage andtherefore the two elements 12 and 14 can be tied together at their midpoints by rod 16 and the two elements 12 and 14 can be tied together attheir mid points by rod 17, as shown in Fig. 4, skipping the mid-pointsof the dipole 13-13, as indicated at 1818, without any harm to theantenna, and, at the same time, give a better impedance match to thetransmission line. Fig. 6 illustrates diagrammatically the electricaleffect which this novel tie-up obtains on the low band. The heavy linesindicate that part of one side, namely 13, enters into the operation ofthe opposite side of the antenna. As a result, a signal striking the oneside of the middle dipole is fed through the wires 19 to the other sideof the outer dipoles and radiated to add to the signal on the middledipole, thereby giving a regenerative effect capable of building up on avery weak signal. It is possible that one wave striking the antenna maybe used to reinforce several subsequent waves, whereas it is known thatonly one rein forcing action is obtainable with an in-line antenna.

The reflector placed behind the improved antenna operates as describedin the copending application to:

(1) Permit gain on desired channels;

(2) Reject interference from the rear of the antenna, and

(3) Permit a combination of rejection of interference and gain onchannels concerned.

It is believed the foregoing description conveys a good understanding ofthe objects and advantages of our invention. The appended claims havebeen drawn to cover all legitimate modifications and adaptations.

We claim:

1. An antenna suitable for television use comprising an uprightsupporting mast, three pairs of substantially horizontal metallic rodelements carried by said mast in insulated relation thereto and to oneanother and extending from opposite sides of the mast in alignedrelationship, the pairs being in evenly vertically spaced substantiallycoplanar relationship, and a substantially vertical metallic rod elementon each side of the mast rigidly interconnecting the three rod elementstogether at their midpoints but so as to electrically connect themidpoints of the top and bottom rod elements through said vertical rodelement while leaving the middle rod element in insulated relationshipto the vertical rod element, each pair of aligned horizontal rodelements being electrically cross-connected with the next pair ofaligned horizontal rod elements.

2. An antenna suitable for television use as set forth in claim 1wherein said pairs of horizontal rod elements are spaced a half-wavelength, and each pair measures one wave length from end to end thereof.

3. An antenna suitable for television use comprising an uprightsupporting mast, more than two pairs of substantially horizontalmetallic rod elements carried by said mast in insulated relation theretoand to one an other and extending from opposite sides of the mast inaligned relationship, the pairs being in evenly vertically spaced,substantially coplanar relationship, and a substantially verticalmetallic rod element on each side of the mast rigidly interconnectingthe midpoints of said horizontal rod elements but so as to electricallyconnect the midpoints of only alternate ones of said horizontal rodelements while leaving the horizontal rod element therebetween ininsulated relationship to the vertical rod element, each pair of alignedhorizontal rod elements being electrically cross-connected with the nextpair of aligned horizontal rod elements.

4. An antenna suitable for television use as set forth in claim 3,wherein said pairs of horizontal rod elements are spaced a half-wavelength, and each pair measures one wave length from end to end thereof.

5. A television antenna and reflector combination comprising an antennaconsisting of an upright supporting mast, more than two pairs ofsubstantially horizontal metallic rod elements carried by said mast ininsulated relation thereto and to one another and extending fromopposite sides thereof in aligned relationship, the pairs being inevenly vertically spaced substantially coplanar relation, and asubstantially vertical metallic rod element on each side of the mastrigidly interconnecting the horizontal rod elements at their midpointsbut so as to electrically connect the inidpoints of alternate rodclements while leaving the horizontal rod element therebetween ininsulated relationship to the vertical rod element, each pair ofhorizontal rod elements being electrically cross-connected with the nextpair of horizontal rod elements, said antenna being mounted in a fixed,spaced, substantially parallel relation to a reflector, said reflectorcomprising an upright supporting mast, pairs of substantially horizontalmetallic rod elements carried by said mast in insulated relation theretoand to one another extending from opposite sides thereof in alignedrelationship, the pairs being in vertically spaced substantiallycoplanar relation, a pair of substantially vertical metallic rodelements in substantially parallel spaced relation on each side of themast rigidly and electrically intercom necting the end portions of thehorizontal rod elements so as to define a plurality of loops on eachside of the mast, and means electrically connecting loops on oppositesides of the mast, said last mentioned means being constructed andarranged to electrically connect a selected one or more loops on oneside of the mast with a selected one or more loops on the other side.

6. A television antenna and reflector combination comprising an antennaconsisting of: an upright supporting mast, more than two pairs ofsubstantially horizontal metallic rod elements carried by said mast ininsulated relation thereto and to one another and extending fromopposite sides thereof in aligned relationship, the pairs being inevenly vertically spaced substantially coplanar relation, and asubstantially vertical metallic rod element on each side of the mastrigidly interconnecting the horizontal rod elements at their midpointsbut so as to electrically connect the midpoints of alternate rodelements while leaving the horizontal rod element therebetween ininsulated relationship to the vertical rod eiement, each pair ofhorizontal rod elements being electrically cross-connected with the nextpair of horizontal rod elements, said antenna having three pairs ofhorizontal rod elements in evenly vertically spaced relation and beingmounted in a fixed, spaced, substantially parallel relation to areflector, said reflector having five pairs of horizontal rod elementsin evenly vertically spaced parallel relation, the first, third andfifth pairs of the latter rod elements being spaced like the three pairsof rod elements of the antenna, and the second and fourth pairs of rodelements of the reflector being mid- 5 way between the first and thirdand third and fifth pairs, respectively, a pair of substantiallyvertical metallic rod elements in substantially parallel spaced relationon each side of the mast rigidly and electrically interconnecting theend portions of the horizontal rod elements so as to define a pluralityof loops on each side of the mast, and means electrically connectingloops on opposite sides of the mast, the said means electricallyconnecting loops on opposite sides of the mast of said reflector beingleeted one or more loops on one side of the mast with a selected one ormore loops on the other side.

References Cited in the file of this patent constructed and arranged toelectrically connect a se- 10 2,558,727

UNITED STATES PATENTS Gothe Sept. 22, 1936 Von Radinger June 27, 1939Posthumus June 18, 1940 Bernet July 3, 1951

